Improved throttle response?

[dgouge773]

Hello everyone, this is my first real post on this site. I'm trying to figure out if taking off my 2 rear converters on my '86 Grand Marquis with improve the throttle response. I cut the muffler and tailpipe off because the car would hesitate and jerk badly under any kind of acceleration. It helped a lot, but I live in a very hilly area of Wisconsin and would prefer not to slam into 2nd or 3rd gear going up an icy hill. My exact plan is to cut the rear converters off, sell them, and use the money to bolt up dual straight pipes with glasspacks at the ends. Does this sound like a good plan? Sorry for the 2 questions, but also, what are these stock converters selling for in the scrap market these days?

[gadget73]

Not really. If the converters aren't clogged, they make very little difference in performance. The motor makes all of 150 hp with single exhaust, so you're just dealing with the basic gutlessness of these cars. Dual exhaust and better rear gearing will help a whole lot. If you've got 2.73 or 3.08 gears, you'll find it struggles on hills a lot more than say a 3.55 or 3.73 gear would.

[dgouge773]

Would the different gear ratio cause me to lose gas mileage? And how many horses would I be looking at with dual exhaust?

[1990LTD]

Not really. If the converters aren't clogged, they make very little difference in performance. The motor makes all of 150 hp with single exhaust, so you're just dealing with the basic gutlessness of these cars. Dual exhaust and better rear gearing will help a whole lot. If you've got 2.73 or 3.08 gears, you'll find it struggles on hills a lot more than say a 3.55 or 3.73 gear would.

How extensive a job is changing the rear gears? If I found 3.55s or even 3.27s or somethings in a yard, could it be swapped cheaply?

[1987cp]

Dual exhaust 5.0 cars got up to 165hp. Still practically nothing, but that's a 10% improvement over 150.

The most popular upgrade with Crown Vic and T-bird people is to strip off the entire top end and install 5.0 HO parts from a Mustang or certain years of Mark VII. 225hp is still quite weak, though, so if you go that route, make sure you can get the parts very cheaply.

What are your long term goals for the car?

[87gtVIC]

one must look at it as if they are gaining 75 horse power over stock. Then it is really good.

[gadget73]

Would the different gear ratio cause me to lose gas mileage? And how many horses would I be looking at with dual exhaust?

Depending on your driving habits, maybe. A 3.73 with mostly highway usage will probably cost you some economy. Mostly stop/go with a lot of hills, I'd be willing to wager no decrese and probably an improvement. Its very much a situational thing.

How extensive a job is changing the rear gears? If I found 3.55s or even 3.27s or somethings in a yard, could it be swapped cheaply?

Shimming and setting preload and pinion depth. Not exactly a job for the faint of heart. Its doable but its not just a bolt-in operation. Cheap is also a relative term, but I'd say probably not. Gear swaps can be pretty involved. Thats something you'd also want to strongly consider a full axle overhaul with new bearings and seals, and if you need axle shafts, thats something else to deal with.

[1990LTD]

It wouldn't be me putting it in, that's for sure. I was thinking more like showing up at my mechanics place with the crap in the back seat and telling him to swap the rear gears Just daydreaming about possible mods..

[gadget73]

Oh, if you do mess with the gears and rebuild the axle, its a good excuse to go with rear disc brakes